Página 1 dos resultados de 42055 itens digitais encontrados em 0.009 segundos

Innate immunity to Paracoccidioides brasiliensis infection

CALICH, Vera Lucia Garcia; COSTA, Tania Alves da; FELONATO, Maira; ARRUDA, Celina; BERNARDINO, Simone; LOURES, Flavio Vieira; RIBEIRO, Laura Raquel Rios; VALENTE-FERREIRA, Rita de Cassia; PINA, Adriana
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
344.9722%
Innate immunity is based in pre-existing elements of the immune system that directly interact with all types of microbes leading to their destruction or growth inhibition. Several elements of this early defense mechanism act in concert to control initial pathogen growth and have profound effect on the adaptative immune response that further develops. Although most studies in paracoccidioidomycosis have been dedicated to understand cellular and humoral immune responses, innate immunity remains poorly defined. Hence, the main purpose of this review is to present and discuss some mechanisms of innate immunity developed by resistant and susceptible mice to Paracoccidioides brasiliensis infection, trying to understand how this initial host-pathogen interface interferes with the protective or deleterious adaptative immune response that will dictate disease outcome. An analysis of some mechanisms and mediators of innate immunity such as the activation of complement proteins, the microbicidal activity of natural killer cells and phagocytes, the production of inflammatory eicosanoids, cytokines, and chemokines among others, is presented trying to show the important role played by innate immunity in the host response to P. brasiliensis infection.

Imunidade ativa e passiva em suínos vacinados contra a leptospirose. Emprego de vacina experimental de subunidade e duas bacterinas comerciais de bactérias completas; Active and passive immunity in swine vaccinated against leptospirosis. Use of an experimental subunit vaccine and two commercial whole culture bacterins

Soto, Francisco Rafael Martins
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 18/12/2006 PT
Relevância na Pesquisa
344.9722%
Foi avaliado o desempenho de vacina de subunidade e bactéria completa antileptospirose em matrizes suínas analisando-se os níveis de anticorpos aglutinantes e neutralizantes. A intensidade e duração da imunidade passiva nos leitões, e ativa nas matrizes suínas foi investigada pela soroaglutinação microscópica (SAM) e teste de inibição de crescimento de leptospiras (ICL) em grupos de animais tratados com vacina experimental de subunidade e leptospira completa produzida com a mesma estirpe e com duas bacterinas comerciais. O experimento foi realizado em duas fases, na primeira, sendo utilizadas 33 matrizes. Os animais foram divididos em três grupos: grupo 1 (n=11):controle; grupo 2 (n=11): recebeu duas doses, em intervalo de 30 dias, de vacina anti-leptospirose constituída da subunidade de lipopolissacarídeo (LPS) de leptospira sorovar Canicola. Grupo 3 (n=11): recebeu duas doses, em intervalo de 30 dias, de uma bacterina de bactérias completas antileptospirose. Na segunda fase foram utilizadas 24 matrizes. Os animais foram divididos em três grupos: Grupo A (n=08): recebeu duas doses, em intervalo de 30 dias, de bacterina comercial anti-leptospirose A. Grupo B (n=08): recebeu duas doses, em intervalo de 30 dias, de bacterina comercial antileptospirose B e Grupo C (n=08): controle. Tanto na primeira fase como na segunda...

Prior Immunity to Homologous and Heterologous Salmonella Serotypes Suppresses Local and Systemic Anti-Fragment C Antibody Responses and Protection from Tetanus Toxin in Mice Immunized with Salmonella Strains Expressing Fragment C

Roberts, Mark; Bacon, Andrew; Li, Jingli; Chatfield, Steven
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /08/1999 EN
Relevância na Pesquisa
346.48387%
We have investigated the effect of preexisting immunity to homologous (Salmonella typhimurium) or heterologous (S. dublin) serotypes of Salmonella on the ability of an attenuated S. typhimurium aroA aroD vector (BRD509) to immunize mice against the heterologous antigen fragment C (FrgC). We studied two strains, BRD847 and BRD937, expressing FrgC carried on plasmids that differ only with respect to the promoter controlling FrgC expression, the nirB promoter in the case of BRD847 and the htrA promoter in the case of BRD937. Mice were preimmunized orally with S. typhimurium BRD509, S. dublin aroA aroD (BRD620), or saline. Forty-four days later, they were immunized orally with BRD847 or BRD937. Prior immunity to S. typhimurium severely depressed the serum immunoglobulin G (IgG) and IgA anti-FrgC response in both BRD847- and BRD937-immunized mice. Mice with existing immunity to S. dublin also had lower IgG anti-FrgC geometric mean titers (GMTs) than did mice preimmunized with saline, but this difference was significant only in the case of mice immunized with BRD937. However, in nonimmune mice or in mice preimmunized with S. typhimurium or S. dublin, the anti-FrgC IgG GMTs were always higher in mice in the BRD937 groups than in the equivalent BRD847 groups. This is reflected in the effect of prior immunity on the ability of oral immunization with BRD847 or BRD937 to protect mice from challenge with a lethal dose of tetanus toxin. All of the mice preimmunized with saline and then immunized with BRD847 or BRD937 survived challenge. Only 20% of the animals immunized with BRD847 and 60% of the mice in the BRD937 group survived tetanus toxin challenge if they were preimmunized with BRD509. Preexisting immunity to S. dublin did not affect the ability of BRD937 to immunize mice against tetanus...

Adaptive Immunity against Listeria monocytogenes in the Absence of Type I Tumor Necrosis Factor Receptor p55

White, Douglas W.; Badovinac, Vladimir P.; Fan, Xin; Harty, John T.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /08/2000 EN
Relevância na Pesquisa
345.8102%
Tumor necrosis factor (TNF) and the type I TNF receptor (TNFRI), p55, are critical for resistance against primary infections with the intracellular bacterial pathogen Listeria monocytogenes. Importantly, however, susceptibility to primary listeriosis in cytokine-deficient mice does not preclude the development or expression of effective adaptive immunity against virulent L. monocytogenes. We used TNFRI−/− mice to study adaptive antilisterial immunity in the absence of interactions between TNF and TNFRI. Our experiments indicate that TNFRI−/− mice survive and clear high-dose challenges with an attenuated strain of L. monocytogenes that is incapable of cell-to-cell spread. Furthermore, TNFRI−/− mice immunized with attenuated L. monocytogenes go on to develop potent adaptive immunity to subsequent high-dose challenges with virulent L. monocytogenes. Interestingly, CD8+ T-cell depletion in vivo inhibits immunity to L. monocytogenes in the spleen but not in the liver of TNFRI−/− mice. The adaptive immune response in these animals is characterized by activation of listeriolysin O-specific CD8+ T cells, which are capable of transferring antilisterial immunity to naive wild-type C57BL/6 host mice. These experiments demonstrate the development and expression of potent CD8+ T-cell-mediated antilisterial immunity in the absence of TNFRI.

Roles of Innate and Adaptive Immunity in Respiratory Mycoplasmosis

Cartner, Samuel C.; Lindsey, J. Russell; Gibbs-Erwin, Julie; Cassell, Gail H.; Simecka, Jerry W.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /08/1998 EN
Relevância na Pesquisa
345.8102%
Current evidence suggests that host defense in respiratory mycoplasmosis is dependent on both innate and humoral immunity. To further delineate the roles of innate and adaptive immunity in antimycoplasmal defenses, we intranasally infected C3H/HeSnJ-scid/scid (C3H-SCID), C3H/HeSnJ (C3H), C57BL/6J-scid/scid (C57-SCID), and C57BL/6N (C57BL) mice with Mycoplasma pulmonis and at 14 and 21 days postinfection performed quantitative cultures of lungs and spleens, quantification of lung lesions, and histopathologic assessments of all other major organs. We found that numbers of mycoplasmas in lungs were associated with genetic background (C3H susceptible, C57BL resistant) rather than functional state of adaptive immunity, indicating that innate immunity is the main contributor to antimycoplasmal defense of the lungs. Extrapulmonary dissemination of mycoplasmas with colonization of spleens and histologic lesions in multiple organs was a common occurrence in all mice. The absence of adaptive immune responses in severe combined immunodeficient (SCID) mice resulted in increased mycoplasmal colonization of spleens and lesions in extrapulmonary sites, particularly spleens, hearts, and joints, and also reduced lung lesion severity. The transfer of anti-M. pulmonis serum to infected C3H-SCID mice prevented extrapulmonary infection and disease...

Protective Cross-Reactive Cellular Immunity to Lethal A/Goose/Guangdong/1/96-Like H5N1 Influenza Virus Is Correlated with the Proportion of Pulmonary CD8+ T Cells Expressing Gamma Interferon

Seo, Sang Heui; Peiris, Malik; Webster, Robert G.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /05/2002 EN
Relevância na Pesquisa
345.8102%
A/Goose/Guangdong/1/96-like H5N1 influenza viruses now circulating in southeastern China differ genetically from the H5N1 viruses transmitted to humans in 1997 but were their precursors. Here we show that the currently circulating H9N2 influenza viruses provide chickens with cross-reactive protective immunity against the currently circulating H5N1 influenza viruses and that this protective immunity is closely related to the percentage of pulmonary CD8+ T cells expressing gamma interferon (IFN-γ). In vivo depletion of T-cell subsets showed that the cross-reactive immunity was mediated by T cells bearing CD8+ and T-cell receptor (TCR) α/β and that the Vβ1 subset of TCR α/β T cells had a dominant role in protective immunity. The protective immunity induced by infection with H9N2 virus declined with time, lasting as long as 100 days after immunization. Shedding of A/Goose/Guangdong/1/96-like H5N1 virus by immunized chickens also increased with the passage of time and thus may play a role in the perpetuation and spread of these highly pathogenic H5N1 influenza viruses. Our findings indicate that pulmonary cellular immunity may be very important in protecting naïve natural hosts against lethal influenza viruses.

Heterologous Immunity in the Absence of Variant-Specific Antibodies after Exposure to Subpatent Infection with Blood-Stage Malaria

Elliott, Salenna R.; Kuns, Rachel D.; Good, Michael F.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /04/2005 EN
Relevância na Pesquisa
345.8102%
We examined immunity induced by subpatent blood-stage malaria (undetectable by microscopy) using the rodent malaria parasite, Plasmodium chabaudi chabaudi, postulating that limited infection may allow expansion of antigen-specific T cells that are normally deleted by apoptosis. After three infections drug cured at 48 h, mice were protected against high-dose challenge with homologous or heterologous parasites (different strain or variant). Immunity differed from that generated by three untreated, patent infections. Subpatently infected mice lacked immunoglobulin G (IgG) to variant surface antigens, despite producing similar titers of total malaria-specific IgG to those produced by patently infected mice, including antibodies specific for merozoite surface antigens conserved between heterologous strains. Antigen-specific proliferation of splenocytes harvested prechallenge was significantly higher in subpatently infected mice than in patently infected or naive mice. In subpatently infected mice, lymphoproliferation was similar in response to homologous and heterologous parasites, suggesting that antigenic targets of cell-mediated immunity were conserved. A Th1 cytokine response was evident during challenge. Apoptosis of CD4+ and CD8+ splenic lymphocytes occurred during patent but not subpatent infection...

Immunogenicity of Heterologous Prime-Boost Regimens Involving Recombinant Adenovirus Serotype 11 (Ad11) and Ad35 Vaccine Vectors in the Presence of Anti-Ad5 Immunity

Lemckert, Angelique A. C.; Sumida, Shawn M.; Holterman, Lennart; Vogels, Ronald; Truitt, Diana M.; Lynch, Diana M.; Nanda, Anjali; Ewald, Bonnie A.; Gorgone, Darci A.; Lifton, Michelle A.; Goudsmit, Jaap; Havenga, Menzo J. E.; Barouch, Dan H.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /08/2005 EN
Relevância na Pesquisa
345.8102%
The high prevalence of preexisting immunity to adenovirus serotype 5 (Ad5) in human populations will likely limit the immunogenicity and clinical utility of recombinant Ad5 (rAd5) vector-based vaccines for human immunodeficiency virus type 1 and other pathogens. A potential solution to this problem is to utilize rAd vaccine vectors derived from rare Ad serotypes such as Ad35 and Ad11. We have previously reported that rAd35 vectors were immunogenic in the presence of anti-Ad5 immunity, but the immunogenicity of heterologous rAd prime-boost regimens and the extent that cross-reactive anti-vector immunity may limit this approach have not been fully explored. Here we assess the immunogenicity of heterologous vaccine regimens involving rAd5, rAd35, and novel rAd11 vectors expressing simian immunodeficiency virus Gag in mice both with and without anti-Ad5 immunity. Heterologous rAd prime-boost regimens proved significantly more immunogenic than homologous regimens, as expected. Importantly, all regimens that included rAd5 were markedly suppressed by anti-Ad5 immunity. In contrast, rAd35-rAd11 and rAd11-rAd35 regimens elicited high-frequency immune responses both in the presence and in the absence of anti-Ad5 immunity, although we also detected clear cross-reactive Ad35/Ad11-specific humoral and cellular immune responses. Nevertheless...

Double-Stranded RNA Induces Sequence-Specific Antiviral Silencing in Addition to Nonspecific Immunity in a Marine Shrimp: Convergence of RNA Interference and Innate Immunity in the Invertebrate Antiviral Response?

Robalino, Javier; Bartlett, Thomas; Shepard, Eleanor; Prior, Sarah; Jaramillo, Guillermo; Scura, Edward; Chapman, Robert W.; Gross, Paul S.; Browdy, Craig L.; Warr, Gregory W.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/2005 EN
Relevância na Pesquisa
345.8102%
Double-stranded RNA (dsRNA) is a common by-product of viral infections and a potent inducer of innate antiviral immune responses in vertebrates. In the marine shrimp Litopenaeus vannamei, innate antiviral immunity is also induced by dsRNA in a sequence-independent manner. In this study, the hypothesis that dsRNA can evoke not only innate antiviral immunity but also a sequence-specific antiviral response in shrimp was tested. It was found that viral sequence-specific dsRNA affords potent antiviral immunity in vivo, implying the involvement of RNA interference (RNAi)-like mechanisms in the antiviral response of the shrimp. Consistent with the activation of RNAi by virus-specific dsRNA, endogenous shrimp genes could be silenced in a systemic fashion by the administration of cognate long dsRNA. While innate antiviral immunity, sequence-dependent antiviral protection, and gene silencing could all be induced by injection of long dsRNA molecules, injection of short interfering RNAs failed to induce similar responses, suggesting a size requirement for extracellular dsRNA to engage antiviral mechanisms and gene silencing. We propose a model of antiviral immunity in shrimp by which viral dsRNA engages not only innate immune pathways but also an RNAi-like mechanism to induce potent antiviral responses in vivo.

Mixed Strain Infections and Strain-Specific Protective Immunity in the Rodent Malaria Parasite Plasmodium chabaudi chabaudi in Mice

Cheesman, Sandra; Raza, Ahmed; Carter, Richard
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /05/2006 EN
Relevância na Pesquisa
346.48387%
Important to malaria vaccine design is the phenomenon of “strain-specific” immunity. Using an accurate and sensitive assay of parasite genotype, real-time quantitative PCR, we have investigated protective immunity against mixed infections of genetically distinct cloned “strains” of the rodent malaria parasite Plasmodium chabaudi chabaudi in mice. Four strains of P. c. chabaudi, AS, AJ, AQ, and CB, were studied. One round of blood infection and drug cure with a single strain resulted in a partial reduction in parasitemia, compared with levels for naïve mice, in challenge infections with mixed inocula of the immunizing (homologous) strain and a heterologous strain. In all cases, the numbers of blood-stage parasites of each genotype were reduced to similar degrees. After a second, homologous round of infection and drug cure followed by challenge with homologous and heterologous strains, the parasitemias were reduced even further. In these circumstances, moreover, the homologous strain was reduced much faster than the heterologous strain in all of the combinations tested. That the immunity induced by a single infection did not show “strain specificity,” while the immunity following a second, homologous infection did, suggests that the “strain-specific” component of protective immunity in malaria may be dependent upon immune memory. The results show that strong...

Sendai Virus Infection Induces Efficient Adaptive Immunity Independently of Type I Interferons

López, Carolina B.; Yount, Jacob S.; Hermesh, Tamar; Moran, Thomas M.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /05/2006 EN
Relevância na Pesquisa
345.8102%
Adaptive immunity in response to virus infection involves the generation of Th1 cells, cytotoxic T cells, and antibodies. This type of immune response is crucial for the clearance of virus infection and for long-term protection against reinfection. Type I interferons (IFNs), the primary innate cytokines that control virus growth and spreading, can influence various aspects of adaptive immunity. The development of antiviral immunity depends on many viral and cellular factors, and the extent to which type I IFNs contribute to the generation of adaptive immunity in response to a viral infection is controversial. Using two strains (Cantell and 52) of the murine respiratory Sendai virus (SeV) with differential abilities to induce type I IFN production from infected cells, together with type I IFN receptor-deficient mice, we examined the role of type I IFNs in the generation of adaptive immunity. Our results show that type I IFNs facilitate virus clearance and enhance the migration and maturation of dendritic cells after SeV infection in vivo; however, soon after infection, mice clear the virus from their lungs and efficiently generate cytotoxic T cells independently of type I IFN signaling. Furthermore, animals that are unresponsive to type I IFN develop long-term anti-SeV immunity...

T-Cell-Independent Humoral Immunity Is Sufficient for Protection against Fatal Intracellular Ehrlichia Infection▿

Bitsaktsis, Constantine; Nandi, Bisweswar; Racine, Rachael; MacNamara, Katherine C.; Winslow, Gary
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
347.03727%
Although humoral immunity has been shown to contribute to host defense during intracellular bacterial infections, its role has generally been ancillary. Instead, CD4 T cells are often considered to play the dominant role in protective immunity via their production of type I cytokines. Our studies of highly pathogenic Ehrlichia bacteria isolated from Ixodes ovatus (IOE) reveal, however, that this paradigm is not always correct. Immunity to IOE infection can be induced by infection with a closely related weakly pathogenic ehrlichia, Ehrlichia muris. Type I cytokines (i.e., gamma interferon, tumor necrosis factor alpha, and interleukin-12) were not necessary for E. muris-induced immunity. In contrast, humoral immunity was essential, as shown by the fact that E. muris-infected B-cell-deficient mice were not protected from IOE challenge and because E. muris immunization was effective in CD4-, CD8-, and major histocompatibility complex (MHC) class II-deficient mice. Immunity was unlikely due to nonspecific inflammation, as prior infection with Listeria monocytogenes did not induce immunity to IOE. Antisera from both wild-type and MHC-II-deficient mice provided at least partial resistance to challenge infection, and protection could also be achieved following transfer of total...

Class II-Restricted Protective Immunity Induced by Malaria Sporozoites▿

Oliveira, Giane A.; Kumar, Kota Arun; Calvo-Calle, J. Mauricio; Othoro, Caroline; Altszuler, David; Nussenzweig, Victor; Nardin, Elizabeth H.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
345.8102%
The irradiated-sporozoite vaccine elicits sterile immunity against Plasmodium parasites in experimental rodent hosts and human volunteers. Based on rodent malaria models, it has been proposed that CD8+ T cells are the key protective effector mechanism required in sporozoite-induced immunity. To investigate the role of class II-restricted immunity in protective immunity, we immunized β2-microglobulin knockout (β2M−/−) mice with irradiated Plasmodium yoelii or P. berghei sporozoites. Sterile immunity was obtained in the CD8+-T-cell-deficient mice immunized with either P. berghei or P. yoelii sporozoites. β2M−/− mice with the BALB/c (H-2d) genetic background as well as those with the C57BL (H-2b) genetic background were protected. Effector mechanisms included CD4+ T cells, mediated in part through the production of gamma interferon, and neutralizing antibodies that targeted the extracellular sporozoites. We conclude that in the absence of class I-restricted CD8+ T cells, sporozoite-induced protective immunity can be effectively mediated by class II-restricted immune effector mechanisms. These results support efforts to develop subunit vaccines that effectively elicit high levels of antibody and CD4+ T cells to target Plasmodium preerythrocytic stages.

Impact of Preexisting Vector-Specific Immunity on Vaccine Potency: Characterization of Listeria monocytogenes-Specific Humoral and Cellular Immunity in Humans and Modeling Studies Using Recombinant Vaccines in Mice ▿ †

Leong, Meredith L.; Hampl, Johannes; Liu, Weiqun; Mathur, Shruti; Bahjat, Keith S.; Luckett, William; Dubensky, Thomas W.; Brockstedt, Dirk G.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
347.03727%
Recombinant live-attenuated Listeria monocytogenes is currently being developed as a vaccine platform for treatment or prevention of malignant and infectious diseases. The effectiveness of complex biologic vaccines, such as recombinant viral and bacterial vectors, can be limited by either preexisting or vaccine-induced vector-specific immunity. We characterized the level of L. monocytogenes-specific cellular and humoral immunity present in more than 70 healthy adult subjects as a first step to understanding its possible impact on the efficacy of L. monocytogenes-based vaccines being evaluated in early-phase clinical trials. Significant L. monocytogenes-specific humoral immunity was not measured in humans, consistent with a lack of antibodies in mice immunized with wild-type L. monocytogenes. Cellular immune responses specific for listeriolysin O, a secreted bacterial protein required for potency of L. monocytogenes-derived vaccines, were detected in approximately 60% of human donors tested. In mice, while wild-type L. monocytogenes did not induce significant humoral immunity, attenuated L. monocytogenes vaccine strains induced high-titer L. monocytogenes-specific antibodies when given at high doses used for immunization. Passive transfer of L. monocytogenes-specific antiserum to naïve mice had no impact on priming antigen-specific immunity in mice immunized with a recombinant L. monocytogenes vaccine. In mice with preexisting L. monocytogenes-specific immunity...

Funktionelle Untersuchungen von Colicin M und seinem Immunitätsprotein; Functional analysis of colicin M and its immunity protein

Römer, Christin
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
Relevância na Pesquisa
346.48387%
Bakteriocine stellen eine große Vielfalt an Protein-Antibiotika dar, die von Bakterien zur Abwehr konkurrierender Bakterien produziert werden. Die Protein-Toxine bestimmter Escherichia coli - Stämme werden als Colicine bezeichnet, sind plasmidcodiert und töten Zellen durch Ausbildung von Poren in der Cytoplasmamembran oder den Abbau von Nukleinsäuren. Colicin M wirkt einzigartig als Phosphatase, die die Murein-Biosynthese inhibiert und so zur Lyse der Zellen führt. In meiner Diplomarbeit wurde die Kristallstruktur von Colicin M bestimmt und es konnte erstmalig gezeigt werden, dass die Aktivität eines importierten Proteins von einem einzigen periplasmatischen Chaperon, FkpA, abhängig ist. Da Colicin M nur die äußere Membran passieren muss, ist es besonders geeignet, den Import von Proteinen in das Periplasma zu studieren. In dieser Arbeit wird Colicin M in der Art seiner Bindung, Aufnahme und Wirkungsweise näher charakterisiert. Es konnte gezeigt werden, dass Colicin M seine Konformation bei der spezifischen Bindung an seinen Rezeptor FhuA in der äußeren Membran ändert. Nachdem es in die Zellen importiert wurde, konnte es aktiv aus dem Periplasma und der Membran extrahiert werden, wobei es nicht möglich war, entfaltetes...

Sovereign Immunity and the Enforcement of International Cultural Property Law

PAVONI, Riccardo
Fonte: Instituto Universitário Europeu Publicador: Instituto Universitário Europeu
Tipo: Trabalho em Andamento Formato: application/pdf; digital
EN
Relevância na Pesquisa
346.48387%
The present paper examines the intersection of the law of State immunity and cultural property issues. The primary interest in undertaking this investigation lies in the fact that, while immunity from seizure and other measures of constraint aims to protect and further the cultural and educational function of State cultural heritage property, immunity from jurisdiction (understood stricto sensu as immunity from suit) may bar legitimate restitution claims brought by individuals who have been unlawfully dispossessed of cultural objects. Therefore, a clear-cut and comprehensive solution to the problems raised by the expanding litigation in this area is not forthcoming. Customary and treaty obligations in the field of cultural heritage, such as the duty to return stolen cultural objects, are inconclusive in that regard and stand in the background as the reference materials guiding the analysis. What seems most needed is instead a wide-ranging balancing exercise that takes into account all of the values, interests and circumstances at stake in art-and-immunity cases. Obviously, this assumes that State immunity for jure imperii acts, such as the expropriation of property in times of armed conflict, should not be regarded as a dogma of contemporary international law. On the contrary...

Declining (the) Subject: Immunity and the Crisis of Masculine Selfhood in Modern France (1870-2000)

Wolfe, Loren Katherine
Fonte: Harvard University Publicador: Harvard University
Tipo: Thesis or Dissertation
EN_US
Relevância na Pesquisa
346.48387%
I locate my dissertation at the critical intersection of philosophy, medical discourse and literature, and anchor it around five intertwining concepts: modernity, subjectivity, masculinity, immunity and Frenchness. I contend that immunity, as a concept at which life and law converge, offers an alternative and largely overlooked episteme shaping contemporary French literary consciousness as a primary regulator/negotiator between health and sickness, belonging and not belonging, volition and involition, and, finally, self and other. I treat immunity metaphorically and scientifically, and then trace the episteme through the works of three French authors—Émile Zola, Albert Camus and Hervé Guibert—all of whom adopt the medical novel as a way of addressing the relationship of the individual to society and to the self. Anne-Marie Moulin frames the immunological revolution as an ever-evolving "semantic event." In this vein, I devote my first chapter to examining how immunity instituted itself as a common trope of "becoming" embraced—and left naturalized—by post-structural thinkers grappling with their corporal limits. This rhetorical turn culminates in Jean-Luc Nancy's characterization of the immune system as the body’s “physiological signature...

Distinct Effects on Diversifying Selection by Two Mechanisms of Immunity Against Streptococcus pneumoniae

Gierahn, Todd; Trzciński, Krzysztof; Flechtner, Jessica B.; Li, Yuan; Thompson, Claudette M.; Ford, Christopher Burton; Croucher, Nicholas Jason; Gouveia, Paulo; Malley, Richard; Lipsitch, Marc
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
347.03727%
Antigenic variation to evade host immunity has long been assumed to be a driving force of diversifying selection in pathogens. Colonization by Streptococcus pneumoniae, which is central to the organism's transmission and therefore evolution, is limited by two arms of the immune system: antibody- and T cell- mediated immunity. In particular, the effector activity of CD4+ TH17 cell mediated immunity has been shown to act in trans, clearing co-colonizing pneumococci that do not bear the relevant antigen. It is thus unclear whether TH17 cell immunity allows benefit of antigenic variation and contributes to diversifying selection. Here we show that antigen-specific CD4+ TH17 cell immunity almost equally reduces colonization by both an antigen-positive strain and a co-colonized, antigen-negative strain in a mouse model of pneumococcal carriage, thus potentially minimizing the advantage of escape from this type of immunity. Using a proteomic screening approach, we identified a list of candidate human CD4+ TH17 cell antigens. Using this list and a previously published list of pneumococcal Antibody antigens, we bioinformatically assessed the signals of diversifying selection among the identified antigens compared to non-antigens. We found that Antibody antigen genes were significantly more likely to be under diversifying selection than the TH17 cell antigen genes...

Immunity in Caenorhabditis Elegans: a Tale of Two Transcription Factors

TeKippe, Michael Jon
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação Formato: 2115642 bytes; application/pdf
Publicado em //2009 EN_US
Relevância na Pesquisa
345.8102%

Recently, the study of invertebrate innate immunity has garnered considerable attention after the discovery that mammalian homologues of the Drosophila melanogaster

Toll pathway play a role in mammalian innate immunity. One invertebrate model system that has begun to be intensely studied is the nematode Caenorhabditis elegans. Immunity in C. elegans has been shown to be inducible in that it responds uniquely to different pathogens. These changes in gene expression require transcription factors in order for certain genes to be transcribed. We utilized an RNA interference screen of potential transcription factors to identify the GATA transcription factor ELT-2 as a possible transcription factor involved in immunity. We then demonstrated that ELT-2 was required for resistance to a wide range of pathogens and was responsible for regulating expression of the C-type lectin clec-67, a marker of immunity.

We also studied another transcription factor known to play a role in C. elegans immune function, the FOXO transcription factor DAF-16. We specifically focused in on the role of DAF-16 in germline-deficient mutants, and we demonstrated that such mutants are resistant to many different pathogens. This led to further investigation of the germline-deficient mutant glp-4...

Imunidade tributária às contribuições sociais destinadas à segurança social das entidades beneficientes de assistência social; Tax immunity on social insurance contributions for the social security of the charitable organization for social assustance

Gonçalves, Rodrigo Prado
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 19/02/2015 PT
Relevância na Pesquisa
346.48387%
O presente trabalho científico possui por escopo estudar a imunidade tributária às contribuições sociais destinadas à seguridade social das entidades beneficentes de assistência social mencionada no artigo 195, §7º, da Constituição Federal de 1988, bem como a abrangência dessa hipótese imunitória aplicável a essas espécies de entidades sem fins lucrativos. A imunidade tributária é uma norma de estrutura contida na Constituição Federal de 1988 que impede que União, Estados, Distrito Federal e Municípios tributem certas pessoas, fatos ou bens. Em outras palavras, as imunidades tributárias são normas constitucionais de incompetência tributária. A Constituição Federal de 1988 elenca inúmeras espécies de imunidades tributárias, dentre as quais a imunidade às contribuições sociais destinadas à seguridade social das entidades beneficentes de assistência social. Sempre que determinada pessoa jurídica enquadrar-se no conceito de entidade beneficente de assistência social e observar as exigências contidas na lei será ela imune. De acordo com a Carta Magna de 1988, consideram-se entidades beneficentes de assistência social as pessoas jurídicas que promovem as ações descritas em seu artigo 203. Neste trabalho científico...